Improvement of the production and quality of Cordyceps javanica conidia for the control of Diaphorina citri adults.

ABSTRACT

This study aimed to evaluate the use of palm kernel meal (PKM) in the traditional solid-state fermentation system to improve the production and quality of Cordyceps javanica conidia. The impact of PKM was determined by measuring conidia yield, viability, hydrophobicity, shelf life, and conidia pathogenicity against Diaphorina citri adults. By supplementing rice grains with 5% palm kernel meal increased the conidial yield by up to 40%, without compromising conidia viability and hydrophobicity. In addition, conidia caused higher levels of mortality by mycosis against D. citri adults (90%), relative to conidia harvested from rice (52%). The conidia recovered from rice/palm kernel meal mixtures also retained viability greater than 90% after storage for 10 months at 4 °C, while the conidia produced on rice reached 80%. Thus, conidia produced in the presence of palm kernel meal can be consumed immediately or in the medium term. Some process advantages of the palm kernel meal as co-substrate in the traditional production system of C. javanica are also mentioned. These results are attractive for improving the mycoinsecticide production process, with excellent cost-benefit and minimal changes in infrastructure and process.